Variations on Slow Switching

Regarding the slow switch experiment, the default interpretation is
that Oscar's water concept is wholly replaced with a twin water
concept (see, e.g., Ludlow 1996, Brueckner 1997). Following Bernecker
(2010), call this the “conceptual replacement”
interpretation. Yet when considering Burge's “preservative
memory,” we saw that Oscar could conceivably retain the water
concept while acquiring an additional concept (even if he cannot discriminate between the two). Call this the
“conceptual addition” interpretation (favored by, e.g.,
Burge 1998, Boghossian 1989, Gibbons 1996). As may be expected, the
details of the slow switch argument vary depending on which
interpretation is adopted.

For instance, under the conceptual addition interpretation,
‘water’ in Oscar's mouth
becomes equivocal: On some occasions it
expresses the water concept, e.g., when Oscar expresses childhood
memories. On other occasions it expresses the twin water concept, e.g.,
when he asks his waiter on Twin Earth for a glass of
“water.” Yet one can also question whether the newer
concept is the twin water concept, specifically. Instead it
may be that the additional concept is disjunctive, in
denoting water or twin water. Alternatively, an
externalist may even suggest that Oscar expresses more than one concept
when he utters ‘water’, or possibly that it is
indeterminate which concept it expresses. (See Bernecker 2010, ch. 6,
for an overview of such options; Brueckner 2000 also is helpful.)

How should we decide among the various interpretations?
Surprisingly, almost no externalist has pursued this question at any
length, but two exceptions are Heal (1998) and Goldberg (2005b) (see
also Burge 1998, n. 13). Though in Heal's case, the aim is not so
much to settle the question, as to illustrate that the issue is really
much more complex than has been admitted.

Consider again Oscar's post-switch utterance:

(W†) Water is the only thing I now drink; however, many
years ago, I drank water fortified by gin.

First, Heal allows that (W†) can be interpreted in the way
suggested earlier, namely, where it confirms the “shifty”
memory view. The basis for this interpretation was the
following.

(1a) The first occurrence of ‘water’ has a twin water
content (since it is used in expressing a thought about the stuff
presently before Oscar).

(2a) The second occurrence of ‘water’ expresses the same
content as the first.

(3a) So, the second occurrence of ‘water’ has a twin
water content.

But one might be just as inclined to reason thus (Heal 1998, p.
101):

(1b) The second occurrence of ‘water’ has a water
content (since it helps to express a memory about the stuff on
Earth).

(2b) The first occurrence of ‘water’ has the same
content as the second.

(3b) So, the first occurrence of ‘water’ has a water
content.

On its face, it is unclear why one argument takes priority over the
other. Indeed, the latter may provide the more appropriate
interpretation, depending on one's purposes (Heal 1998, pp.
101-102). This is one complexity that seems underappreciated.

As a second complication, Oscar's transition from English to
Twin English is not entirely clean-cut. Heal observes: “in the
early two or three days of a switch the victim, asked to indicate what
he meant by ‘water’; would specify a mixed bag by offering
phrases such as ‘what I had a bath in last week’,
‘what is in this glass right now’, ‘what, in its
frozen form, I skated on last winter’, ‘what comes out of
that tap over there’, etc.” (p. 107). And this raises the
question “Under what conditions, then, is a switch
complete?” (p. 107). (The “Triplet Earth” and
“triwater” example on p. 99-100 is relevant here as
well.)

An externalist can recommend some guidelines for untangling these
knots. Most basically, they should be decided by one's
externalist metaphysics of meaning (of the sorts noted
in section 1).[1]
For instance, on Putnam's (1975) externalist semantics, it is
important that the environmental objects referred to“serve also
as standard-setters by resemblance to which…other items deserve
the same label” (Heal 1998, p. 103). (N.B., Putnam himself
speaks of “stereotypes” vs. standard-setters.) Given that,
“our practice of using natural kind terms can exist and have the
features it does only because we have memories of and generally
reliable abilities to re-identify particular specimens” (p. 104).
Against this background, Heal concludes “[t]he ‘slow
switching’ claim then amounts to this: after a while in the new
environment a new set of (remembered and identifiable) specimens from
the new environment will come to play the standard-setting role”
(p. 104). The establishment of stereotypes and the acquisition
of re-identification abilities are the crucial matters, for the
externalist, in determining which concepts figure into which of
Oscar's thoughts, and at what times.

Goldberg (2005b) adds further tentative guidelines on the matter. The
default should be to interpret Oscar in relation to his current
environment, unless there is a defeating condition, e.g., where Oscar
has just been switched from Earth. Another defeating condition might be
when Oscar's justification for a belief is reasonable
only if he is interpreted with respect to the earlier, Earthian
environment. Thirdly, the default may also be overridden if Oscar
intends to be reporting a particular event from memory, and
the event de facto occurred on Earth. This can happen, e.g., if
Oscar's second use of ‘water’ in (W†) is
intended “to pick out the stuff I mixed with gin many years
ago.” (This intention describes Earthian water, even on its
Twin Earth interpretation.) It may be unclear whether either of the
latter two conditions is enough to override the default. Though
Goldberg suggests that either is sufficient if, in
addition, were Oscar informed of the slow switch, he would disavow Twin
Earth interpretations of his utterances and beliefs (roughly put) (2005, p.
114).